Radio receiving system



Feb. 2, 1932. s. s. soNNEBoRN ET AL. 1,843,177

RADIO RECEIVING SYSTEM Filed Jan. 13. 1926 mw. m

N E @EW n THE N mmm wf w 16% A W M 5. muy AJ mrFIlI.

L g .5MM Mb `Q "Q -`-igmwm im m E l ww A A ww vv mt wf :WN Cim. NNW `m 'wave length as well as for another.

Patented Feb. 2, 1932 UNITED STATES PATENT OFFICE SOL S. SONNEBORN, OF EAST ORANGE, AND HENRY G. RICHTER, OF ROSELLE PARK,

NEW JERSEY RADIO RECEIVING SYSTEM Application filed January 13, 1926. Serial' No. 81,129.

This invention relates to radio receiving sets and is particularly directed to the radio frequency portion thereof. It lis recognized that the physical confines of a receiving set more or less of necessity pre-supposes a loose coupling between the coils going to make up the various resonating circuits that is, between Vthe coils of different stages. It is an obj ect of this invention advantageously to employ this loose coupling between the coils of the resonating circuits for purposes of regeneration. It is, however, a further object to compensate or adjust this loose coupling in such a way that as the set is tuned to receive broadcasting at different wave lengths, the most desirable adjustment may be had for ope n simpler language it is also an objective to eliminate that degree of oscillation producing squeals, while at the same time providing for extremely sharp tuning.

In understanding this invention, it should be borne in mind that it is contemplated that the coils referred to are the antenna coil involved in a local circuit tuned by a variable condenser and the secondary coils of the interstageradio frequency vcoupling transformer likewise adapted to be tuned by a variable condenser. In the embodiment of the invention illustrated, wherever there is a primary associated with one of these Secondary coils, its coupling therewith is fixed. A preferred construction comprises two tele,-

scoping tubes nested together, the inner l carrying 'the primary winding and the outer tube carrying the secondary coil. The automatically adjusted Vvariable coupling forming an important factor of this invention is that effected by varying the axial relationship between two groups of these tuned coils, for example, by leaving the antenna coil and the second transformer secondary coil fixed, moving the intermediate secondary coil to vary its lcoupling to the said first two coils commensurately with the rotation of the rotor of the variable condenser associated lwith this intermediate coil.

To this end the linvention contemplates 'means for varying the loose coupling between that the closeness of the coupling shall vary inversely as the capacity employed in the resonating circuit. In other words, in carrying out the objective of thev invention, the closeness of the coupling is automatically `5 varied inversely as to wave length or directly as to frequency. It is a still further objective of the invention to provide an adjustable mounting for some of the coils, independentV from the means for varying the coupling beso tween coils. Still further objectives of the invention are to improve in general radio receiving sets, all of which will be pointed out more in detail in the following claims which are directed to the illustrative embodiment of the invention described in the following specification in connection with the accompanying drawings solely for the purpose of illustration and not limitation.

In the drawings, Figure l is a circuit diagram of the complete receiving set. Figure 2 is a diagram showing the condenser adjustments and relative positioning of the three coils for minimum condenser value; Figure 3 is a similar diagram showing the positioning for maximum condenser value; Figure 4 is a diagram at right angles to the showing of Figure 3, showing the relative positioning for maximum condenser value.

In the receiving set illustrated, six triodes so A1, A2, AS, A4, A5, A6 are employed and may be connected in accordance with standard practice as indicated in the diagram of Figure l in which triodes A1 to A3 are radio frequency, and A., to A6, audio frequency. In the radio frequency part of the set three resonating circuits B1, B2, B3 are illustrated,-

B1 for the antenna l, B2 for the first stage and B3 for the second stage of amplification. In these circuits are employed respectively coils C1, C2 and C3, and variable condensers 131,1)2 and D3. Physically, coil C1 need have but a single winding, while coils C2 and C3 are secondary coils of a radio frequency i transformer, and each is associated withL a primary coil P1 and l?2 in the usual way. In a preferred embodiment of the invention each of the coils C is wound on an appropriate tube of insulating material, and, when a primary coil is to be associated therewith, it 1s upon an inserted smaller insulating tube, as

' planes passing through the axes of the varicommon in the art. The end coils C1 and C3 are preferably adjustably mounted upon clamps or brackets 4 which adjustably clip the tubes carrying the windings C1 and C2, and may have a fixed adjustmentthrough means of the screw nuts 5, preferably to fix the coils C1 and C3 so that their axes are substantially paralleland-.extend at "about 45` degrees with the horizontal and preferably so that their axes lie respectively in the same able condensers Dl andDg. c i, j,

The intermediate coil CL'is positionedv preferably midwaybetween the coilsGl andCS vand for minimum capacity adjustment as in dicated in Figure Qlhas itsaxis parallel to thoseof 'coils' C1 and C3. This coil C2, however, is preferably mounted upon a stem 6, forming an extension from the shaft of the variable condenservDg, andso as to move throughout 180 degrees of rotation commensurate therewith as the condenser varies from minimum to maximum capacity, and furthermore, so thatthe positioning of this coil C2 will gradually change from a position of maximum coupling to minimum coupling relatively to coils C1 and C3, or so that its axis varies from parallelism with the end coils to a position at right angles with the axes of the end coils, as shown in Figs?) and 4. j

In adjusting the set for best performance it is sometimes foundl that it is best to adjust the axes of the end coils C1 and C3 so that they may vary a little one way or another vfrom 45. It is for this purpose that the adjustable clamps 4 are provided. Y Once the adjustment is found the coils should be fixed. It is there- Y fore to be understood that for some purposes of the invention this adjustability for the end coils .is not essential but provides an easy means of properly positioning the end coils. It is further to be understood that although three sets of coils for three resonating circuits are indicated7 and it is the coil of intermediate position that has the rotary adjustment, this `need of necessity for all purposes not'be so.

The'middle coilmightbel fixed in position and the two end l'coils rotate, butitvis preferred that vthe intermediate coil' rotate, as the mechanical structure foraccomplishing the 'necessary adjustment is thereby simplified. It is also contemplated that for all purposes it is not essential that therotatable coil be made angularly commensurate with that of the condenser; for example only a 180 degree rotationV for the coil is required while it is possiblethat the operating shaft for the condenser might require a 360 degree rotation for Varying the value of the condenser lfrom minimum to maximum. In fact all these variations in detail are contemplated as falling within the scope. of thisinvention.

What I claim and desire to secure by United States patent rights is:

l. In a tuned `radio frequency broadcast receiving set a plurality of triode tubes, a plurality of associated resonating circuits one for eachstage of amplification andeach cornprising a variablecondenser and a coil, means for varying the coupling of one of said coils with the other of said coils between a minimum anda maximum in proportion tothe condenser value of the condenser adjustment of one of said variable condensers. v2. In a tuned radio frequency broadcast receiving setta plurality of associated resonatingcir'cuits one for each stage of amplification and eachcomprising acoil andfone'comprising'Y a variable condenser; means for varying the relative positioning of two of said coils from a position in which their axes are substantially parallel to a relative vposition.V in which theiraxes are substantially at right angles contemporaneously with a variation of said variable condenser from minimum capacity to maximum capacity.

3. In a tuned radio frequency broadcast receiving set an assemblage of three coils mounted side `by side but separated one from the other; means for adjusting the endmost coils and fixing them in a position in which their axes areapproximately parallel and extend at approximately 45 degrees to the' horizontal; means for adjustably rotating theintermediate coil so as to vary its position from a position in which its axis is substantially parallel to the axes of said end coils throughout an intermediate range of movement until its axis is substantially at right angles to the axes of said end coils. A y

4. The structure'. described in claim 8 and further characterized by the fact that avariable condenser is associated with said intermediate coil and is mechanically coupled there- Vsaid end kcoils-to a position substantially at right angles with the axis of said end coils.

5. In a tuned radio frequency broadcast receivingfsetv a plurality of associated resonating circuits, one for each stage of amplification and each comprising a coil and a condenser, said coils to be loosely coupled one with another for radio frequency in both; and a ysingle means for increasing the capacity of one or more of said condensers and at the same time decreasing the coupling between said coils. -v

6. In a tuned radio frequency broadcast receiving s-et a plurality of associated resonating circuits, one foreach stage of amplifica- ,tionv and each comprising a coil more or less loosely y'coupled one with another; means for tuning said circuits comprising in addition provisions for decreasing the coupling between said coils commensurately with an increase in wave length and vice versa.

7. In a multi-stage transformer coupling, radio frequency system, comprising several tunable coils, one for each stage; a variable condenser including a rotor for varying the capacity reactance and in association one with each of said coils; means for operatively linking one group of said coils to rotate each with its associated rotor while the remaining number of said coils are fixedly mounted, whereby the loose magnetic coupling between groups of said coils, each associated with a separate stage of amplification, is varied commensurately with the rotation of said rotors.

8. A tuned radio frequency receiver comprising three triodes in a tunable grid circuit for each said triode comprising a radio frequency secondary coil and a variable condenser having a stator and a rotor variable in capacity effect by relative rotation between a maximum and a minimum capacity value; means for mounting said radio frequency coils, one set in relatively fixed position and one set upon said rotors, while maintaining said coils separated and each associated with its corresponding stage, whereby electromagnetic loose coupling between said coils varies between a maximum and a minimum as the capacity of said condensers varies between a minimum and a maximum. 9. A receiver as described in claim 8 and 35 further characterized by the fact that the mounting for said relatively xed radio frequency coils is manually adjustable to facilitate an initial adjustment of the degree of loose coupling between the adjustable coil and 40 said relatively fixed coil.

SOL S. SONNEBORN. HENRY Gr. RICHTER. 

